Monday, 8 July 2019

10th Class Chemistry Notes Chapter 3 Organic Chemistry

10th Class Chemistry Notes Chapter 3
Here are the 10th Class Chemistry Notes Chapter 3 Organic Chemistry pdf download or you can also read online.

Q.1 What is vital force theory who proposed it?
 Ans: According to vital force theory organic compounds could not be prepared in laboratories because they were supposed to be synthesized under the influence of a mysterious force called vital force inherent only in living things In early 19h century Swedish chemist Jacob Berzelius proposed this theory.
 Q.2 Who rejected the vital force theory and how?
 Ans: Vital force theory was rejected by Wohler in 1828 when he synthesized the first organic compound urea from inorganic substance by heating ammonium cyanate (NH CNO) NH,C NH-C-NH
 Urea
 Q.3 Define organic chemistry.
 Ans: The branch of chemistry which deals with the study of hydrocarbons and their derivatives is known as organic chemistry"Q.4 What are different types of formula by which we can represent organic compounds?
 Ans: Organic compounds can be represented by following four types of formula a) Molecular formula, b) Structural formula
 c) Condensed formula d) dot and cross formula.
 Q.5 Define molecular formula.
 Ans: The formula which represents the actual number of atoms in one molecule of the organic compound is called molecular formula. For example molecular formula of butane is C.H.
Q.6 Define structural formula.
 Ans: Structural formula of a compound represents the exact arrangement of the different atoms of various elements present in molecule of a substance Structural formula of butane is
Q.7 Define condensed formula.
 Ans: The short form of formula that indicates the group to cach carbon atom in a straight chain or branched chain is called a condensed formula.
 For example condensed formula for n- butane is
 CH-CH2 CH2- CH
 OR
 CH:-(CH3)2 -CH
Q.8 What is dot and cross formula.
 Ans: "The formula which shows the sharing of electrons between various atoms of one molecule of the organic compound is called dot cross formula or electronic formula"
 For example: cross and dot formula for butane is
Q.9 Write down the names of classes in which organic compounds are classified.
 Ans: All organic compounds are broadly classified into two classes.
 a) Open chain or Acyclic compound:
 b) Closed chain or Cyclic compound:
 Q.10 Define open chain compound. Explain their types Ans: Open chain compounds are those in which the end carbon atoms are not joined with each other in this way they for long chain of carbon atoms.
 There are two types of open chain compound
 a) Straight chain compounds.
 b) Branched chain compounds:
 a) Straight chain compounds.
 Compounds in which carbon atoms link with each other through a single, double or triple bonds forming a straight chain
 For example HC-CH2-CH CH
 (Straight chain butane)
 b) Branched chain compounds.
 "compounds in which there is a branch along a straight chain"
 For example:
 CH
 (Branched chain) (Iso-butane)
 Q.11 What are aliphatic compounds?
 Ans: Open chain compounds in which only single bond is present are also called aliphatic compounds.
Q.12 Define cyclic compounds explain their types.
 Ans: Those compounds in which the carbon atoms at the ends are not free and they join to form rings
 They are further divided into two classes.
 a) Homocyclic compound b) Heterocyclic compound
 Q.13 Define Homocyclic compounds. Explain their types.
 Ans: Compounds contain rings which are made up of only one kind of atoms, i.e, carbon atoms are called Homocyclic compounds.
 There are two types of Homocyclic compounds.
 a) Aromatic compounds b ) Alicyclic compounds
 Q.14 Define aromatic compound. Give example
 Ans: "Those homocyclic compounds in which at least one benzene ring having six carbon atoms with three alternate double and single bonds are called aromatic compound Example benzene ring
Q.15 What is the meaning of term aromatic?
 Ans: Term aromatic is derived from Greek word Aroma" which means fragrant"
 Q.16 What are benzenoid compounds?
 Ans: Aromatic compounds are also called benzenoid compounds
Q.17 Define alicyclic or non benzenoid Compounds.
 Ans: Carbocyclic or homocyclic compound which do not have benzene ring in their molecules are called alicyclie or non benzenoid compounds.
 CH
Q.18 Define Heterocyclic compound. Give example Ans: Cyclic compounds that contain one or more atoms other than carbon atoms in their rings are called heterocyclic compounds.
 For examples
 Pyridine
 Thiophene
 Q.19 Define catenation.
 Ans: The ability of carbon atoms to link with other carbon atoms to form long chains and large rings is called catenation.
 Q.20 What are two basic conditions for elements to exhibit catenation?
 Ans: Two basic conditions for cutenation are
 a) Element should have valency two or more greater than two b Bond made by an element with its own atoms should he stronger than the bonds made by the element with other atoms especially oxygen.
Q.21 Define Isomerism. Give examples.
 Ans: Isomerism
 The compounds having same molecular formula but different arrangement of atoms in their molecules or different structural formulae are called isomers and the phenomenon is
Q.22 Why and how carbon complete its octet?
 Ans: To get stability, carbon completes its octet by making four covalent bond with other atoms
 Q.23 Why melting and boiling points and of organic compounds are very low?
 Ans: Melting points and boiling point of organic compounds are low because carbon forms weak covalent bond with other carbon atoms which break up easily Q.24 Why organic compounds are poor conductor of electricity?
 Ans: Due to presence of covalent bonds. organic compounds are poor conductor of electricity
 Q.25 How we get organic compounds from Earth's crust?
 Ans: We get organic compounds by Destructive distillation of coal and by Fractional distillation of Petroleum.
Q.26 What are the reasons for the formation of millions of organic compounds?
 Ans: Organic compounds have large diversity due to a) catenation b) isomerism ) weak covalent bond
 d) Multiple bonds forming ability of carbon.
 Q.27 What is coal?
 Ans: Coal is blackish, complex mixture of compounds of carbon, hydrogen and oxygen. It also consists of small amount of nitrogen and sulphur compounds
Q.28 Define Carbonization.
 Ans: Conversion of wood into coal is called carbonization. It is very slow bio-chemical process. It takes place in the absence of air under high pressure and high temperature over a long period of time
 Q.29 Write down the names of different types of coal.
 Ans: Coal is of following four types
 a) Peat b) lignite c) Bituminous d) anthracite
 Q.30 Define Destructive Distillation?
 Ans: Breakdown of coal into smaller compounds by strong heating of coal in the absence of air is called destructive distillation.
Q.31 Write down the names of product obtained by destructive distillation of coal.
 Ans: Products obtained by destructive distillation of coal are a) Coal Gas b) Ammonical Liquor Coal tar d) coke
Q.32 What is Pitch? What is its use?
 Ans: Black residue of coal tar is called Pitch. In common words it is also known as "look"
 It is used for surfacing of roads and roofs.
Q.33 What is petroleum? What is its composition?
 Ans: Petroleum is a dark brownish or greenish black coloured viscous liquid. It is a complex mixture of several solid, liquid or gaseous hydrocarbons in water mixed with salts and earth particles
 Q.34 What is composition of natural gas?
 Ans: Natural gas is a mixture of low molecular mass hydrocarbons. The main component about 85% is methane. along with other gases i.e. ethane. butane. propane
Q.35 What types of compounds are synthesized by plants?
 Ans: Living plants synthesized macro-molecule g. carbohydrates, proteins, oils and vitamins plants also produce gums, Rubber, medicines etc.
 Q.36 What are alkanes? Give their general formula?
 And: Alkanes are saturated hydrocarbons or paraffins (Para little , affines affinity).
 Their general formula is C,H2 Where n is the number of carbon atoms.
Q.37 Define alkyl radical. How they formed?
 Ans: Alkyl Radicals are derivatives of alkanes they are formed by removal of one of the hydrogen atom of an alkane and are represented by "R.". Their general formula is CH
Q.38 What is Functional group? Give example.
 Ans: "An atom or group of atom or presence of double or triple bond which determines the characteristics properties of an organic compound is known as the functional group For example OH hydroxyl group is the functional group of alcohol which give characteristic properties of alcohols
 Q.39 What is functional group for aldehyde and ketone?
 Ans: Functional groups for aldehyde and ketone areQ.40 What is functional group for ether and carboxylic compounds?
 Ans: Functional group for ether is (R - O-R) and for carboxylic compound is (R-C-OH
 Q.41 What is ester linkage?
 Ans: Organic compounds in which carbon has
 linkage is called ester linkage
 RCOR
 These compounds are called esters
 0.42 What are amines give examples?
 Ans: The organic compounds containing carbon, hydrogen and nitrogen as a functional group (-NH) are called amines. (NIT) is functional group and their general formula is R NH
 Examples:
Q.43 What is functional group for an alkyl Halide?
 Ans: Functional group for alkyl halide is R-X where R is alkyl radical and X is halogen i.e.
 F. CI. Br or I., etc
 Q.44 Give functional group for alkene and alkyne.
 Ans: For alkene double bond ( =) is functional group and triple bond () is functional group for alkyne
 e.g. H C CH2 (ethene)
 HC CH (ethyne)
 0.45 Write down the name of tests for detection of double bond (unsaturation)?
 Ans: i) Bromine water test and
 ii) Baeyer's test is used to detect unsaturation
Q.46 What are identification test for alcoholic group?
 Ans: i) sodium metal test and
 ii) Ester formation test is used to test alcoholic group.
 Q.47 How carboxylic group is identified?
 Ans: Carboxylic group is identified by
 i) Litmus test
 ii) Sodium bicarbonate test.
 Q.48 Give identification test for aldehyde group?
 Ans: Aldehydes are identified by
 i) Sodium bisulphate test
 i) Fehling's solution Test
 Q.49 What are identification test for ketonic group?
 Ans: ketone group is identified by
 i. Phenyl hydrazine Test
 ii.Sodium Nitroprusside Test

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